Drilling-machine.



No. 865,148. PATENTED SEPT. 3, 1907.

' E. ALSLEBEN.

DRILLING MACHINE.-

APPLICATION FILED MAY 23, 1907.

2 S HEETSSHEET l.

Array/mm 1n: NORRIS PETERS'CG, WASHINGYON, n. c

No. 865,148. PATBNTED SEPT. a, 1907.

E. ALSLEBEN. DRILLING MACHINE. APPLICATION FILED MAY 23 1907 2SHEETS-SHEET 2w WWW- UNITED STATES PATENT OFFICE.

ERNST ALSLEBEN, OF GI-IARLOTTENBURG, NEAR BERLIN, GERMANY, ASSIGNOR OFONE- HALF TO MAX STEINBERG, OF OHARLOTTENBURG, NEAR BERLIN, GERMANY.

DRILLING-MACHINE Patented Sept. 3, 1907.

Application filed May 23,1907. serialNo. 375,239.

To all whom it may concern:

Be it known that I, EnNs'r ALsLnBEN, a subject of the German Emperor,and a resident of Oharlottenburg, near Berlin, 11 Spielhagenstrasse, inthe German Empire, engineer, have invented certain new andusefulImprovements in Drilling-Machines, of which the following is aspecification.

The invention relates to an electrically operated stone drillingmachine, the feed bar of which is arranged in the hollow driving shaft.

Stone drilling machines are known in which the drill pressure isregulated automatically by means of a spring interposed between feedspindle and the drill. It is also usual in stone drilling machines toinclude a friction clutch in the feed mechanism, which clutch isautomatically thrown out when a given drill pressure is exceeded.

In accordance with the present invention, the friction clutch which isincluded in the transmission gear of the feed bar is dependent upon thepressure regulating spring in such a manner that the clutch is thrownout, that is to say the feed bar is disconnected from the countered. Thedanger of breaking the drill owing to i the sudden change in thecharacter of the stone is here obviated by the cooperation of thefriction clutch and the pressure regulating spring. As soon as thespring is overloaded by an excessively fast feed, the friction clutch isthrown out, thereby disconnecting the feed mechanism from the motor.

In accordancewith this invention, the hand feed gear is preferablyprovided with a clutch adapted to be thrown in and out by hand in orderto render it independent of the mechanical feed when the clutch is disconnected, so that it may be used independently. When the clutch isthrown in, however, the hand feed may still be utilized for assistingthe mechanical feed. The arrangement is such that the hand feed may bethrown into gear without it being necessary to stop the motor feed gear.Accordingly, there is no break in the operation.

The object of the invention is illustrated by way of example in theaccompanying drawing, in which Figures 1 and 2 represent longitudinalsections through the machine at right angles to each other. Fig. 3 is alongitudinal section, and Fig. 4 a side view of the ends of the drillbar and the feed bar, illustrating the movable relation of said drillbar in the feed bar. Fig.

5 is a longitudinal section on a larger scale, on line 55 of Fig. 2,showing the friction clutch inserted in the transmission gear incombination with the hand feed mechanism. Fig. 6 is an enlarged crosssection on line 6-6 of Fig. 2, through the several bars guided onewithin the other. Fig. 7 is a cross section on line 77 of Fig. 2,looking downwardly; and Fig. 8 is a perspective detail of the hand wheelclutch.

The hollow shaft 1, operated by the electric motor, is mounted in ballbearings in the casing. The motor consists of an armature 100 attachedto hollow shaft 1, and field magnets 101 attached to the case 6. Thefeed bar 2 is inclosed in the hollow shaftl, and the drill spindle 3(which is connected in the manner hereinafter described with the feedbar by the interposition of a spring for regulating the operativepressure on the drill) is inclosed in the feed bar 2, The feed bar 2 istoothed for effecting the feed.

The shaft 1 has rigidly attached to it the driving worm wheel 11,meshing with the driving wheel 1.2, and rotating the transverse shaft13. The feed'transmission gear is driven from the shaft 13 by the pinion14 meshing with the pinion 15 of the shaft 16, The lattercarries apinion 17 which meshes with the teeth 18 on the feed bar 2. In orderthat the pressure of the feed mechanism may not thrust the feed bar 2 toone side, a pinion 19 is mounted on the shaft 16 and meshes with apinion 20 on a shaft 21 mounted in the casing 6 of the drill on theopposite side of the feed bar. This shaft 21 carries a pinion 22 whichmeshes with the teeth 18 on the feed bar 2. Owing to this driving of thebar 2 from two opposite sides, any one-sided pressure is avoided.

The feed bar 2 carries, at its end (see Figs. 2 and 3) an adjustable cap23 inclosing a spring 24, the ends of which bear against two rings 25and 26which are provided with ball bearings, oneset of which act againstthe upper end 27 of the cap 23, and the other set against a collar 28 ona bar 29, which is coupled with the drill bar 3 by the adjustableclamping clutch 31, 33, at the end, and which latter parts are termedthe spindle bar. Under normal conditions, the collar 28 also bears bymeans of a ball bearing 30 against the end of the feed bar 2. In a knownmanner, the spring 24 provides for a uniform application of pressure tothe drill.

The provision of the clutch 31, 33, presents the advantage that on theone hand the spindle 3 may readily be released from the machine andremoved without the necessity for taking the machine apart, and on theother hand that the spindle 3, and accordingly the drill also, may beadjusted in common relatively to the driving mechanism, and arranged atany desired distance from the casing.

If the drill spindle 3 and consequently the drill 35, say a diamondcrown drill, is fed forward, and if the greater than the pressureexerted by the spring 24, the

drill spindle 3, together with the spindle bar 29 coupled with it, areable to move longitudinally, while compressing the spring 24, as shownin Fig. 3. If the resistance diminishes, that is to say when it againcorresponds to the normal working pressure, (the utmost limit of whichis defined by the tension of the spring 24) the spindle bar 29 and thespindle 3 will gradually return to the position shown in Fig. 1.

Inside the hollow shaft there is provided a driver tube 36see Fig.6which is arranged between the spindle bar 29 and the feed bar 2. Thistube is connectcd by a collar 37 on its lower end with the hollow shaft1 in such a manner as to constitute a rigid whole therewith. The collar37 is bored for the passage of the spindle 3. As shown in Fig. 6, thedriver tube 36 is connected by keys 38 with the spindle bar 29 in such amanner that the latter is able to move in the longitudinal direction,but is obliged to participate in the retary movement of the driver tube36. Accordingly, as on the one hand the tube 36 is connected with thedriving shalt 1, and on the other hand the driven spindle bar 29 isconnected with the tubular spindle 3 by the clamping clutch 31, 33, thecommon rotation of all the parts shown in Fig. 6, with the exception ofthe feed bar 2, is obtained. This feed bar 2 is prevented fromrotatingsee Figs. 2, 6 and 7owing to the fact that projections 40 (on aring attached to the casing):

engage in longitudinal recesses 39 in the feed bar.

In case the regulation of the feed provided for by the spring 24 is notsuflicient, that is to say, if the spring 24 has been completelycompressed owing to an excessive resistance, in accordance with theinvention a second means of regulation is provided for preventingbreakage of the tool, the drill or feed bar, the feed mechanism or otherparts of the machine. This means consists of a friction clutch insertedin the transmission gear, and which becomes operative as soon as thespring 24 has been compressed to a certain extent. This arrangement isshown in Fig. 5. In this construction the worm wheel 12, driven by thehollow shaft 1, is mounted loosely upon the shaft 13. The two parts arecoupled by means of friction plates 41, 42, which are connected with theshaft 13 by means of grooves and feathers 43, 44, in such a manner as tobe axially displaceable, and are pressed by means of a spring 46 againstthe collar 45 on the shaft 13. the spring 46 may be varied by means ofthe adjusting nuts 47 mounted on the shaft 13, in order to bring theaction of this friction clutch into a definite relationship with theaction of the spring 24. It is obvious that after the spring 24 has beencompressed, the motive power disconnects the clutch 41, 42, so that theworm wheel 12 is able to rotate freely on its shaft 13, and thetransmission gear consequently comes to rest.

In order to adjust the feed bar 2 by hand independently of the feedmechanism, or in conjunction therewith, a journal 48, Figs. 5 and 8, isformed on the end of the shaft 13, and is made hollow and mounted in abushing sleeve 49 on which the driving wheel 14 is fixed by means of akey 50. The sleeve 49 is coupled with the hollow journal 43 by means ofa locking clutch consisting of a T-bar 51, which by means of springpressure is caused to engage in recesses 53 in the journal The tensionof 48, and recesses 53 of the sleeve 49 and of the hub 58 of the handwheel 59 fixed on this sleeve. The locking clutch bar 51 is mounted bymeans of a rod 54 and a head 56 in the central recess in the journal 48,and a spring 55 maintains the locking clutch bar 51 engaged with lockingrecesses 53, 53 This spring bears on the one hand against the head 56and on the other hand against a fixed ring 57 inserted in the cavity inthe journal 48. By means of the handle 52, the locking clutch bar 51 maybe caused to occupy the position represented in broken lines in Fig. 5,and full lines in Fig. 8, which withdraws it from the locking apertures,and by being then rotated through 90, the clutch is held open. Afterthis disconnection, the hand wheel 59 and sleeve 49 are able to rotatefreely on the shaft 13, so that by means of the feed driving wheel 14,the feed bar 2 and the drill spindle 3 may be adjusted in eitherdirection independently of the feed mechanism. The hand feed gear mayalso be used even when the mechanical feed is in gear, say for example,when soft stone is encountered, which can be worked at a higher speed.The hand feed then assists the mechanical feed. As soon as hard stone isagain reached and the resistance consequently increases, and if theextreme limit of the resistance of the spring 24 is attained, thefriction clutch 41, 42, is thrown out, so that even with the conjointaction of the hand and mechanical feeds, no breakage of any part of themachine will occur.

The drill spindle is preferably supported in a special bearing 60, Fig.1, outside the casing 6. This is particularly advisable when the spindleis specially long or is to operate with a long feed. The distance sepa-1 shaft 66 provided with a hand wheel 67. By rotating the hand wheel 67,the worm nuts are thereby rotated. By this means the yoke 60, 61, may beadjusted in a simple and convenient manner.

It will of course be understood that the details of the stone drillingmachine described above may vary largely. This is particularly the caseas regards the construction of the motor, and the details of the gear.In the construction here illustrated the arrangement of the spring 24between ball bearing presents the advantage that the drill spindlerotates'very easily in the feed bar 2, so that the feed is effected withvery little loss of energy; in other words the efficiency is very high.

What I claim as my invention and desire to secure by Letters Patent ofthe United States is:

1. A rotary drilling machine, comprising a rotating hollow drivingshaft, a tubular and toothed feed bar arranged therein, a rotary drivertube arranged in the tubular feed bar and having a sliding key, agrooved and slidnbly connected hollow bar arranged in the driver tube, adrill spindle arranged inside said slidably connected and grooved bar, aback-thrust pressure regulating spring arranged concentrically behindthe drill spindle and its surrounding grooved bar and between them andthe feed bar, to be compressed by the drilling strain, a toothedtransmission gear meshing with the tubular and toothed feed bar and afriction clutch arranged in the transmission gear and adapted to yieldunder a more than normal compres sion of the spring behind the drillspindle and its inclosing' hollow bar;

2. A rotary drilling machine, comprising a rotating hollow drivingshaft, a tubular and toothed feed bar ar ranged therein, a rotary drivertube arranged in the tubular feed bar and having a sliding key, agrooved and slid ably connected hollow bar arranged in the driver tube,a drill spindle arranged inside said slidably connected and grooved bar,a l)acl th1ust pressure regulating spring arranged concentrically behindthe drill spindle and its sur rounding grooved bar and between them andthe feed bar to be compressed by the drill strain, a toothed transmission gear meshing with the hollow and toothed feedbar and derivingmotion from the outer driving shaft, a friction clutch arranged in thetransmission gear and adapted to yield under a more than normalcompression of the back-thrust spring, said friction clutch having itsshaft extending through the casing and provided with a hand wheel and arigid interlocking clutch and means for connecting' or disconnectingsaid hand wheel to the shaft of the friction clutch at the will of theoperator.

In Witness whereof I have hereunto set my hand in the presence of twowitnesses.

ERNST ALSLIDBEN.

Witnesses HENRY HAsPER, \VOLDEMAR HAUPT.

